FIG. 28 is a schematic structural view showing a reflecting mirror antenna device that conducts the mechanical drive scanning with respect to rotary axes in an azimuth direction and an elevation direction disclosed in, for example, Takashi Kitsuregawa, “Advanced Technology in Satellite Communication Antennas: Electrical & Mechanical Design”, ARTECH HOUSE INC., pp.232-235, 1990.
Referring to FIG. 28, reference numeral 61 denotes a main reflection mirror; 62 is a sub-reflection mirror; 63 is a primary radiator; 64 is a circularly polarized wave generator; 65 is a polarization divider; 66 is a receiver; 67 is an elevation shaft rotary joint; 68 is an azimuth shaft rotary joint; 69 is a transmitter; 70 is an elevation shaft rotary mechanism; and 71 is an azimuth shaft rotary mechanism.
Subsequently, an operation will be described. A signal outputted from the transmitter 69 is inputted to the polarization divider 65 through the rotary joints 68 and 67, and thereafter transformed into a circularly polarized wave from a linearly polarized wave by the circularly polarized wave generator 64 and then radiated into air through the primary radiator 63 and the sub-reflection mirror 62 by the main reflection mirror 61. Also, an electric wave received by the main reflection mirror 61 is transformed into the linearly polarized wave from the circularly polarized wave through the sub-reflection mirror 62 and the primary radiator 63 by the circularly polarized wave generator 64, inputted to the polarization divider 65 and thereafter enters the receiver 66.
Because the main reflection mirror 61, the sub-reflection mirror 62, the primary radiator 63, the circularly polarized wave generator 64 and the polarization divider 65 can be driven within a wide angular range by the rotary mechanisms 70, 71 and the rotary joints 67, 68 without deteriorating the electric characteristics, an antenna beam can be transmitted while scanning over a wide angle. Also, because the main reflection mirror 61, the sub-reflection mirror 62, the primary radiator 63, the circularly polarized wave generator 64, the polarization divider 65 and the receiver 66 can be driven integrally within a wide angular range by the rotary mechanisms 70 and 71, they can receive an electric wave coming from the wide angular range.
In a conventional antenna device, because the circularly polarized wave generator 64, the polarization divider 65 and the receiver 66 are located on the rotary joints 67, 68 and the rotary mechanisms 70, 71, and those circuits, the main reflection mirror 61, the sub-reflection mirror 62 and the primary radiator 63 are rotated integrally, there arises such a problem that the height of the antenna device from the azimuth shaft rotary mechanism 71 increases and it is difficult to downsize the antenna device and to make the attitude of the antenna device low.
The present invention has been made to solve the above-mentioned problems, and therefore an object of the present invention is to obtain a mechanical drive reflecting mirror antenna device that enables the downsizing, the low attitude and wide-angle scanning and is high in performance.